To improve performance of a microprocessor, an integrated circuit always keeps high-speed development of miniaturization and diversification. However, a reduction in device size and an increase in device density also cause some inevitable problems, for example, a signal delay and interconnect crosstalk. Due to high power consumption and a waste of energy caused by usage of an electrical interconnection medium, a requirement of high performance and low costs for a device in the semiconductor industry gradually cannot be met. It is found that optical interconnection can effectively resolve these problems and bring about many new functions to a conventional integrated circuit. Therefore, silicon photonics becomes an important research subject of a future optoelectronic integrated circuit.
Silicon is a foundation stone of a microelectronic platform, is also indispensable for optoelectronic integration, and has advantages of high integration and low costs. Oxides of the silicon are excellent insulating materials, have a relatively high refractive-index difference, and may be used to guide light. However, the silicon is an indirect bandgap semiconductor and has very low efficiency in light absorption and emission; in addition, carrier mobility of the silicon is not high, leading to limitations to an application involving a high speed. On the contrary, a III-V compound semiconductor has a direct bandgap structure and high electron mobility, and a low dimensional system of the III-V compound semiconductor, for example, a multi-quantum well or a quantum dot, brings about much excellent performance to an optical gain, and brings about diverse changes to a device performance parameter by means of adjustment on material composition and optimization on a low dimensional structure. The III-V compound semiconductor may be used to produce a optoelectronic device such as a laser or a solar cell, and an electronic device, such as a high electron mobility transistor.
A monolithic integration technology for producing a III-V semiconductor device is epitaxially growing a III-V material on a silicon substrate, to produce a device. However, because there are significant lattice mismatch and thermal mismatch between the silicon and a III-V material such as gallium arsenide or indium phosphide, directly growing the III-V material on the silicon leads to high-density threading dislocations, causing a degradation of device performance and a reduction in reliability.